This invention relates to a process for the continuous production of composite cheese.
Extrusion has been used for many years in cheesemaking, particularly in the manufacture of cheese sticks from goat's milk curd and for the extrusion of Italian cream cheese of the mozzarella type. In cases such as these, extrusion is used solely to make pieces of a single type of curd.
It has already been proposed to make composite products having a cheese core, for example filled cereals or meat, by co-extrusion. The techniques involved are illustrated by patents and patent applications EP-A 169 919, EP-A 177 175 and U.S. Pat. No. 3,480,445. Although the exact nature of the filling is not specified, it is processed cheese capable of withstanding heat treatment because the composite product is subsequently cooked.
Processes are also known in which a processed cheese is injected with a colored curd of a different type at the filling head (cf. for example U.S. Pat. Nos. 2,777,124 and 2,872,324). According to FR-A 2,516,356, two different types of curd are coagulated under dynamic conditions in tubular elements and portions are discharged at the top of the tubes as the strand of coagulum advances. It is not possible with this method to control the properties of the curd in the absence of draining. In addition, in view of the fragility of curds in the process of formation, this technique is not applicable in practice to the efficient and continuous production of portions of co-extruded cheeses.
According to patent application FR-A 2 603 457, an already ripened pressed cheese is treated at approximately 80.degree. C. in the presence of ultrafiltered whey proteins to produce a texture which enables it to be hot-extruded.